It is well known that many electronic components and magnetic information-storage materials are extremely sensitive to stray and/or random electrostatic discharges. Such discharges can destroy the components usefulness; it may also destroy or distort information stored in magnetic form.
Such sensitive components and materials are susceptible to harmful discharges during packaging, shipment, storage, and other handling procedures. Conventional precautions include grounding the devices in question during shipping and building protection into the devices with zeno diodes to provide protection from static discharge. Other precautions include the use of a Faraday cage, a mesh or screen fashioned from a conductive metal. The cage is then placed over the shipping container, or made an integral part thereof.
Another recognized method is described in U.S. Pat. No. 4,241,829, issued to Hardy, et al., Dec. 30, 1980, and expressly incorporated herein by reference. The patentee describes a box with a continuous conductive coating overlying substantially all of interior and exterior surfaces and a convoluted foam liner impregnated with a conductive material; the patentee further requires that the conductive material in the foam form a continuous conductive path with the coating setting up a continuous conductive path between the exterior surfaces and the articles in the container. The patentee teaches that conductive coating and the conductive material in the foam should be a solution including both carbon and graphite.
Other art-disclosed applications are found in the specifications of U.S. Pat. Nos. 4,160,503; 4,211,324; 4,293,070; and 4,482,048; all of the foregoing being expressly incorporated herein by reference.
Many other systems employing elemental carbon are also known. For example, U.S. Pat. No. 3,868,313, issued to P. J. Gay, Feb. 25, 1975, discloses a cathodic protection system comprising applying an electrically insulating coating on the substrate followed by the application of an electrically conductive coating applied over the insulating coating. A D.C. voltage is then applied between the metal substrate and the conductive coating.
U.S. Pat. No. 3,151,050, issued Sept. 19, 1964, discloses methods for cathodic protection for vehicles and components in storage. The method comprises the application of an electrically conductive paint to the metal to be protected. The paint is a suspension of carbon, maganese dioxide, ammonium chloride and an organic filler and a solvent such as methyl-ethyl-ketone. A second coating of resin containing metallic copper is then applied, followed by a final coat of paint or enamel. Lastly a D.C. voltage is applied between the conducting paint and the metal base.
U.S. Pat. No. 4,035,265, issued July 12, 1977, to J. A. Saunders discloses electrically conductive paint compositions employing graphite and colloidal carbon. The graphite is subjected to wet grinding so as to reduce the graphite to thin platelets. The colloidal carbon employed consists of particles having a size from 20 to 50 millimicrons. The final composition (including the article it is applied to) is used as a heat source when electrical current is passed through the coating.
Other efforts at carbon-containing coatings are found in
(1) U.S. Pat. No. 3,505,263, which discloses finely divided calcined petroleum coke in a polymer latex binder;
(2) U.S. Pat. No. 3,404,019, which discloses the use of fluid petroleum coke as a filler or pigment in polymeric compositions;
(3) U.S. Pat. No. 2,730,597, which discloses resistance elements which optionally employ various materials in a resin base;
(4) U.S. Pat. No. 4,476,265, which discloses poly (arylene sulfide) compositions which contain a "black carbonaceous pigment";
(5) U.S. Pat. No. 4,444,837, which discloses coating or sealing-type plastisols which contain carbon dust as a filler;
(6) U.S. Pat. No. 3,391,103, which discloses phenolic resin compositions which employ "oxidized carbon particles";
(7) U.S. Pat. No. 3,615,754, which discloses an ink which employs 2 to 10 percent of ground coke; and
(8) U.S. Pat. No. 3,444,183, which discloses a film forming composition made from a heat-resistant polymer and a dispersion of carbon particles.
All of the foregoing are expressly incorporated herein by reference.